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<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
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    <script>
      const num1 = NaN; // not a number
      const num2 = 10 - 5 - "abc";

      console.log(num1);
      console.log(num2);
    </script>
  </body>
</html>
